Caregivers who perform more caregiving tasks or spend more time performing these activities (i.e., greater caregiving intensity) are more stressed, and therefore should have poorer health outcomes. However, results of studies are inconsistent. This might result from operationalizing caregiving intensity as a simple count of the number of caregiving tasks performed, which ignores the fact that these tasks may vary in emotional and physical stress. Further, persons who are healthier are more likely to take on more caregiving tasks, reflecting the Healthy Caregiver Hypothesis. The proposed R21 study will adapt conventional measures of caregiving intensity to develop new measures that better reflect stress associated with specific caregiving tasks, and will use analytic approaches from occupational epidemiology for reducing the Healthy Worker Effect bias to separate the health effects of caregiving intensity from respondents' health status. We will interview 30 older (aged 60+) persons in the Boston MA area who are currently caregiving to a relative with Alzheimer's Disease (AD), Parkinson's Disease (PD), or other chronic condition. The interview will include conventional task-based measures of caregiving intensity, i.e., assisting the care recipient with each of 7 instrumental and basic activities of daily living (I/ADLs), and questions asking whether it is emotionally and/or physically difficult to help with each I/ADL task. We will use cognitive interview techniques to probe the thought processes underlying participants' responses regarding their assessment of the difficulty or stress associated with performing each I/ADL task. Using this information, an expert panel will create weighted measures of emotional and physical caregiving intensity. We will assess the validity of these new measures using general- and caregiving-specific stress scales collected from these participants, as well as data from an existing study of AD and PD caregivers. We will compare new measures to conventional measures of caregiving intensity in associations between a) current caregiving intensity, and b) cumulative and lagged cumulative caregiving intensity with mortality and functional decline in the Caregiver-Study of Osteoporotic Fractures (CG-SOF), a prospective cohort study of 1069 older women caregivers and non-caregivers who were followed for 12+ years. Hypotheses will address comparisons of the associations between new and conventional measures of caregiving intensity (current and cumulative) with mortality and functional decline, as well as associations of combinations of emotional and physical caregiving intensity on these outcomes. This study will not only shed light on the health effects of caregiving intensity, but will lay the groundwork to apply these new measures to other datasets, types of caregivers, and different health outcomes.